This week at TreeHugger: A nice little touch in the EPEAT Gold certified Apple Macbook and Macbook Pros: The Energy Saver icon has changed. Google has a message for other data center operators: Raise the thermostat. And finally, something you don't see everyday: Girls in bikinis swimming with tigers. Apparently the big cats love to play in a pool.Apple decided to make its manufacturing operations greener lately, and for that they must be applauded. But it wouldn't be Apple if they didn't think of the little design details too. Early adopters have noticed that on the version of OS X shipped with the new Macbooks and Macbook Pros the Energy Saver icon has been changed from an inefficient incandescent lightbulb to a CFL. Most data centers operate in a temperature range between 68 and 72 degrees, and some are as cold as 55 degrees. Savings can be calculated with this rule of thumb (according to Mark Monroe of Sun Microsystems): "Data center managers can save 4 percent in energy costs for every degree of upward change". So going from 70 degrees to 80 degrees could, in theory, mean a 40% saving in cooling energy costs (though real-world results might vary from place to place). Traditionally, trainers have struggled to build an attachment with the largest of the big cats but The Institute of Greatly Endangered and Rare Species, or TIGERS, near Miami, claims to have overcome the problem by encouraging both tigers and humans to swim together in a specially adapted pool with glass sides. More details and photos of the tigers swimming with their trainers here. TreeHugger's EcoModo column appears every Tuesday on Gizmodo.